1. Technical Field
The present invention relates to a ride height adjustment device for a bicycle saddle and more particularly to a height adjustment device for a bicycle saddle.
2. Description of Related Art
In addition to a means of transportation, the purposes of bicycles nowadays come in two categories: leisure and race. Leisure-oriented bicycles have lenient requirements of saddle height, as they only require that saddle height can be adjusted easily and quickly before a ride and that the saddle can be quickly and precisely positioned after the adjustment of saddle height. Race-oriented bicycles require that saddle height can be fine-tuned during a race; for example, when racing uphill, cyclists have to ensure that the tread angles of their legs, thighs, and arms must match the distance between the saddle and each pedal, so as to render the tread smooth and easy. In short, race-oriented bicycles must be lightweight, effective in changing speed, and capable of fine-tuning saddle height during a ride.
Referring to FIG. 1, there is shown a schematic view of a conventional height adjustment device for a bicycle saddle. The height adjustment device comprises a hydraulic cylinder 10, a vertical post 11, a cylinder shaft 12, a support 13, a saddle 14, an adjustment rod 15, a pin 16 and a relief valve 17. The end of the hydraulic cylinder 10 is coupled to the bottom of the vertical post 11 from inside. The cylinder shaft 12 of the hydraulic cylinder 10 extends upward to protrude from the top of the vertical post 11. The cylinder shaft 12 is coupled to the support 13 from outside the vertical post 11. The saddle 14 is disposed on the support 13. The adjustment rod 15 is pivotally coupled to the support 13 by a pin 16. The front end of the adjustment rod 15 abuts against a relief valve 17 of the cylinder shaft 12. The adjustment rod 15 can be operated and swung about the pin 16 which functions as the fulcrum. The front end of the adjustment rod 15 presses and drives a hydraulic valve 17 to descend, so as to start a cycle of releasing the pressure accumulated inside the hydraulic cylinder 10. When the vertical post 11 is mounted on a triangular frame of the bicycle, the cylinder shaft 12 bears the rider's body weight, such that hydraulic pressure is accumulated inside the hydraulic cylinder 10 (to therefore decrease saddle height,) whereas the relief valve 17 is pressed and driven downward by the adjustment rod 15 to thereby start the cycle of releasing the pressure accumulated inside the hydraulic cylinder 10, thus driving the cylinder shaft 12 to extend upward (to therefore increase saddle height.) As described above, the hydraulic cylinder 10 bears the rider's body weight to thereby effectuate accumulation of pressure. The rider rotates the adjustment rod 15 to start the cycle of releasing the pressure accumulated inside the hydraulic cylinder 10, such that saddle height can be fine-tuned to a limited extent during the ride. However, in practice, during a race, it is risky for the rider to free a hand which is otherwise gripping the handlebar for balancing and steering the bicycle and use the hand to rotate the adjustment rod 15 in attempt to adjust saddle height. In view of this, the prior art discloses connecting an adjustment cord between the adjustment rod 15 and the handlebar such that, during a ride, the rider may pull the adjustment cord from the handlebar to rotate the adjustment rod 15 and thereby operate the hydraulic cylinder 10 for adjusting saddle height. However, the adjustment cord is long and thus tends to entangle itself with the triangular frame; as a result, the adjustment cord is inept and predisposed to failures. According, the present invention aims to overcome the aforesaid drawbacks of the prior art.